KMZ files are very similar to ZIP files - they allow you to package multiple files together. And they also compress content to speed up file download. This allows you to bundle images along with your KML file if you want.
This video covers some of the basics of KMZ files. For the full tutorial, see http://earth.google.com/outreach/tutorial_kmz.html
This Content Originally Published by a land surveyor to Land Surveyors United Network